# rf205_compplot¶

Addition and convolution: options for plotting components of composite pdfs.

Author: Wouter Verkerke
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Sunday, November 27, 2022 at 11:06 AM.

In [ ]:
%%cpp -d
#include "RooRealVar.h"
#include "RooDataSet.h"
#include "RooGaussian.h"
#include "RooChebychev.h"
#include "RooExponential.h"
#include "TCanvas.h"
#include "TAxis.h"
#include "RooPlot.h"
using namespace RooFit;


## Setup composite pdf¶

Declare observable x

In [ ]:
RooRealVar x("x", "x", 0, 10);


Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and their parameters

In [ ]:
RooRealVar mean("mean", "mean of gaussians", 5);
RooRealVar sigma1("sigma1", "width of gaussians", 0.5);
RooRealVar sigma2("sigma2", "width of gaussians", 1);
RooGaussian sig1("sig1", "Signal component 1", x, mean, sigma1);
RooGaussian sig2("sig2", "Signal component 2", x, mean, sigma2);


Sum the signal components into a composite signal pdf

In [ ]:
RooRealVar sig1frac("sig1frac", "fraction of component 1 in signal", 0.8, 0., 1.);
RooAddPdf sig("sig", "Signal", RooArgList(sig1, sig2), sig1frac);


Build Chebychev polynomial pdf

In [ ]:
RooRealVar a0("a0", "a0", 0.5, 0., 1.);
RooRealVar a1("a1", "a1", 0.2, 0., 1.);
RooChebychev bkg1("bkg1", "Background 1", x, RooArgSet(a0, a1));


Build exponential pdf

In [ ]:
RooRealVar alpha("alpha", "alpha", -1);
RooExponential bkg2("bkg2", "Background 2", x, alpha);


Sum the background components into a composite background pdf

In [ ]:
RooRealVar bkg1frac("sig1frac", "fraction of component 1 in background", 0.2, 0., 1.);
RooAddPdf bkg("bkg", "Signal", RooArgList(bkg1, bkg2), sig1frac);


Sum the composite signal and background

In [ ]:
RooRealVar bkgfrac("bkgfrac", "fraction of background", 0.5, 0., 1.);
RooAddPdf model("model", "g1+g2+a", RooArgList(bkg, sig), bkgfrac);


## Setup basic plot with data and full pdf¶

Generate a data sample of 1000 events in x from model

In [ ]:
RooDataSet *data = model.generate(x, 1000);


Plot data and complete PDF overlaid

In [ ]:
RooPlot *xframe = x.frame(Title("Component plotting of pdf=(sig1+sig2)+(bkg1+bkg2)"));
data->plotOn(xframe);
model.plotOn(xframe);


Clone xframe for use below

In [ ]:
RooPlot *xframe2 = (RooPlot *)xframe->Clone("xframe2");


## Make component by object reference¶

Plot single background component specified by object reference

In [ ]:
model.plotOn(xframe, Components(bkg), LineColor(kRed));


Plot single background component specified by object reference

In [ ]:
model.plotOn(xframe, Components(bkg2), LineStyle(kDashed), LineColor(kRed));


Plot multiple background components specified by object reference Note that specified components may occur at any level in object tree (e.g bkg is component of 'model' and 'sig2' is component 'sig')

In [ ]:
model.plotOn(xframe, Components(RooArgSet(bkg, sig2)), LineStyle(kDotted));


## Make component by name / regexp¶

Plot single background component specified by name

In [ ]:
model.plotOn(xframe2, Components("bkg"), LineColor(kCyan));


Plot multiple background components specified by name

In [ ]:
model.plotOn(xframe2, Components("bkg1,sig2"), LineStyle(kDotted), LineColor(kCyan));


Plot multiple background components specified by regular expression on name

In [ ]:
model.plotOn(xframe2, Components("sig*"), LineStyle(kDashed), LineColor(kCyan));


Plot multiple background components specified by multiple regular expressions on name

In [ ]:
model.plotOn(xframe2, Components("bkg1,sig*"), LineStyle(kDashed), LineColor(kYellow), Invisible());


Draw the frame on the canvas

In [ ]:
TCanvas *c = new TCanvas("rf205_compplot", "rf205_compplot", 800, 400);
c->Divide(2);
c->cd(1);